1. Field of the Invention
The present invention relates to bicycles, and more particularly to chain drives therefor. 2. Description of the Prior Art
Conventional chain drives for bicycles normally employ a single pedal operated sprocket in combination with a single driving sprocket mounted on the hub of the rear wheel. On tandem bicycles, it is conventional to employ two pedal operated cranks having interconnecting chain drives as well as an additional drive on one side of the bicycle to the rear wheel. Racing bicycles commonly employ a single chain drive on one side of the bicycle.
It has been found that the single chain drive arrangements in racing bicycles suffer from a loss of conversion efficiency between the torque applied to the pedals and the power actually applied to rotate the wheel. This is thought to be due to the pedal operated crank flexing some under operation stress. It has been discovered that stiffening the crank assembly through the use of a symmetrically arranged, double crank system provides for an improvement in this conversion efficiency.